Polymer shrink tubes and novel uses therefor

ABSTRACT

Novel polymer shrink tubes, such as fluoropolymer shrink tubes and novel uses thereof. The polymer shrink tubes include at least one three-dimensional pattern formed along at least a portion of the inner surface of the tube. The polymer shrink tubes can be used for, for example, embossing a pattern into a polymer tube. Further use includes, for example, forming a catheter with at least one channel located in the catheter wall.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of commonly owned and copendingapplication Ser. No. 11/073,053, filed Mar. 4, 2005.

FIELD OF THE INVENTION

This invention relates to polymer shrink tubing. Such shrink tubing canbe used for, among other things, the manufacture of catheters.

DESCRIPTION OF RELATED ART

The use of delivery catheters to provide various treatments to a patientis well known. Such delivery catheters have a variety of well-known usessuch as, for example, PTA and PTCA treatment, stent delivery, etc. Manydelivery catheters are guided to the treatment location through apreviously placed guide catheter. Moreover, it is also known to advancediagnostic catheters, angiographic catheters, and steerable catheters toa treatment location through a previously placed guide catheter.

The guide catheter will typically have a centrally located lumen, withthe delivery catheter passed through the centrally located lumen to thetreatment site. In view of this, it is common for the inner surface ofthe guide catheter that defines the centrally located lumen to becomprised of a low friction material, such as polytetrafluoroethylene(PTFE). Moreover, to provide structural support guide catheters usuallyare metal reinforced using, for example, a metal braid or coil wrappedabout the low friction material. It is not uncommon for the metalreinforcement to be embedded by an outer polymer material that definesthe outer wall portion of the guide catheter.

Recently, it has been suggested to use guide type catheters for certainstroke therapies, wherein the guide catheter is delivered, for example,to a patient's carotid artery. Various treatment devices, such asdelivery catheters, balloon-on-a-wire devices, thrombectomy removaldevices, etc., can be guided to the treatment site through one or morelumens provided in the guide catheter. Moreover, such guide catheterscan include an inflatable member at the distal end thereof to occludeblood flow in the selected carotid artery.

Examples of such stroke therapy catheter constructions are illustratedin, for example, commonly owned U.S. Pat. Nos. 6,206,868; 6,423,032;6,540,712; and 6,295,989.

Such catheter constructions can present manufacturing challenges. Forexample, catheter constructions as shown, for example, in commonly owned

U.S. Patent Application Publication Nos. 2003/0040704A1; 2003/0040694A1;and 2003/0040705A1, can include, for example, at least an inflationlumen in the catheter wall, which inflation lumen will be incommunication with the inflatable member at the distal end of thecatheter. Further, the catheter wall can be a polymer material thatembeds a metal reinforcement. Moreover, a PTFE inner liner material candefine a centrally located lumen.

Providing one or more lumens in the catheter wall of such constructionsis extremely difficult. One method of providing lumens in the catheterwall is described in commonly owned and copending U.S. PatentApplication Publication No. 2004/0193139, published Sep. 30, 2004, whichdiscloses a polymer film wrapping process to produce such catheters. Thecatheter can be formed by placing a thin-walled PTFE liner tube over amandrel. A wire support structure (e.g., braid, ribbon, coil, etc.) canthen be placed over the thin-walled tube. Over the wire supportstructure is placed a thermoplastic material that is caused to embed thewire support structure. As taught in this commonly owned patentapplication, at least one lumen, or channel, in the catheter wall can beformed by a laser cut into a thermoplastic material defining the outercatheter wall. Thereafter, a polymer film is applied to (e.g., wrappedabout) the catheter wall to close the channel and form thelongitudinally extending lumen in the catheter body. Another method offorming lumens in the catheter wall includes, for example, placing asmall, hollow tube, such as polyimide tube, adjacent the wire supportstructure and then embedding the wire support structure and small tubeinto the thermoplastic material.

The present invention provides, among other things, unique methods offorming such catheter constructions that overcome the problems discussedabove.

SUMMARY OF THE INVENTION

The invention relates to polymer shrink tubing and novel uses therefore.One aspect of the invention is a tube comprising a fluoropolymer shrinktube having an inner surface and at least one three-dimensional patternformed along at least a portion of the inner surface of the tube. In anaspect of the invention, the three-dimensional pattern comprises atleast one rib formed along the inner surface. The at least one rib canbe longitudinally extending, spirally extending, etc.

In a further aspect of the invention, the invention includes a tubecomprising a polymer shrink tube having an inner surface and at leastone rib formed along the inner surface, the rib extending from the innersurface and having a height of about 0.5 mils or less, more preferablyless than about 0.2 mm.

A further aspect of the invention includes a catheter comprising aninner liner comprising fluoropolymer (e.g., PTFE) tubing. Preferably thefluoropolymer tube is an extruded PTFE tube. The tube having a proximalend, a distal end, an inner surface and an outer surface; an outerpolymer tube having a proximal end, a distal end, an inner surface andan outer surface, wherein the inner surface of the outer polymer tube ispositioned over the outer surface of the fluoropolymer tube; wherein atleast one channel is formed in the outer polymer tube, the at least onechannel preferably measuring about 7 by about 15 mils (0.007″×0.015″)and extending for at least a portion and preferably a majority of thelength of the catheter; and polymer film covering at least a portion andpreferably a majority of the length of the at least one channel, thusforming a lumen in the outer polymer tube.

In a still further aspect of the invention, the invention includes amethod of creating an external, embossed pattern on the exterior of acylindrical device comprising: providing a polymer tube having at leastone exterior surface; providing a polymer shrink tube having an innerand an outer surface, the inner surface having at least onethree-dimensional pattern thereon; placing the polymer shrink tubearound the polymer tube; applying sufficient energy to the shrink tubeso as to shrink the shrink tube around the exterior of the polymer tubewhile causing at least a portion of the at least one three-dimensionalpattern to become embossed into the exterior surface of the polymertube. The applied energy softens the polymer tube material and shrinksthe shrink tube, thus leading to embossing the pattern into the polymertube. This method is particularly suitable for forming catheters such asthe guide catheters discussed above.

DESCRIPTION OF THE DRAWINGS

The operation of the present invention should become apparent from thefollowing description when considered in conjunction with theaccompanying drawings in which:

FIG. 1 shows in partial perspective view a polymer shrink tube accordingto the present invention;

FIG. 2 is a schematic cross-section taken along lines 2-2 of FIG. 1;

FIG. 3 is a schematic cross-section of the use of a polymer shrink tubeaccording to the invention;

FIG. 4 is a schematic cross-section of a further use of a polymer shrinktube according to the present invention;

FIG. 5 is a schematic cross-section of a catheter according to thepresent invention; and

FIG. 6 is a longitudinal cross-section of a catheter according to thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

A first aspect of the invention is a tube comprising a fluoropolymershrink tube having an inner surface and at least one three-dimensionalpattern formed along at least a portion of the inner surface of thetube. In a further aspect of the invention, the three-dimensionalpattern can comprise at least one rib (such as at least onelongitudinally extending rib) formed along the inner surface of thetube. Suitable fluoropolymer materials include, for example, fluorinatedethylene propylene (FEP), fluoroelastomers such as VITON®fluoroelastomers (DuPont Dow Elastomers), ethylene tetrafluoroethylene(ETFE), perfluoroalkoxy (PFA), and polytetrafluoroethylene (PTFE). Thefluoropolymer shrink tube is shown in partial perspective view inFIG. 1. FIG. 2 is a cross-section schematic drawing taken along lines2-2 of FIG. 1. As shown in the figures, the three-dimensional patternformed along at least a portion of the inner surface of the tube 10 isindicated by 1, and in this case, is a longitudinally extending ribwhich can extend for essentially the entire length of the tube. Otherthree-dimensional patterns are envisioned by the present invention, suchas, for example, spirally extending ribs, as well as a plurality ofthree-dimensional patterns, such as two or more ribs.

By “shrink tube having at least one three-dimensional pattern formedalong at least a portion of the inner surface of the tube” it is meantto include longitudinally extending, hollow tubes having at least oneprotuberance, recess, or otherwise three-dimensional pattern, on theinner surface of the tube. The tube will exhibit some shrinkage of itsinner diameter upon exposure to suitable energies, such as heat.Longitudinal shrinkage is not a requirement according to the invention,although it may be desirable. Therefore, “shrink tube” will include apolymer tube that will exhibit some shrinkage of its inner diameter uponexposure to suitable energy and may also exhibit some longitudinalshrinkage upon exposure to suitable energy. It is desirable for theshrink tube to shrink in a predictable manner such that thethree-dimensional pattern is predictably retained upon exposure to thesuitable energy.

Polymer shrink tubes can be made by, for example, well-known extrusionprocesses. Typically such tubes will be formed having a first innerdiameter. The tube is then expanded to a second inner diameter (referredto as the “expanded inner diameter”). Upon application of suitableenergy the inner diameter will shrink back to about the first innerdiameter (referred to as the “retracted inner diameter”).

As stated above, the shrink tubes can comprise, for example, thefluoropolymer materials listed above. The fluoropolymer shrink tubeswill shrink when heated to an appropriate temperature or exposed toother suitable energy forms. For example, the following shrink tubeswill shrink at about the listed temperature or temperature range. VITON®fluoroelastomer, about 120° C.; ETFE, about 175° C.; PFA, about 204° C.;FEP, from about 210 to about 260° C.; PTFE, from about 325 to about 340°C. A particularly attractive fluoropolymer tube comprises FEP.

In a further aspect of the invention, the invention includes a cathetercomprising an inner liner comprising fluoropolymer (e.g., PTFE) tubinghaving a proximal end, a distal end, an inner surface defining agenerally centrally located catheter lumen and an outer surface; anouter polymer tube having a proximal end, a distal end, an innersurface, and an outer surface; wherein the inner surface of the outerpolymer tube is positioned over the outer surface of the fluoropolymertube; wherein further at least one longitudinally extending channel isformed in the outer polymer tube, the at least one channel (preferablymeasuring about 7 by about 15 mils) extending for at least a portion andpreferably a majority of the length of the catheter; and polymer filmcovering at least a portion and preferably a majority of the length ofthe at least one channel; thus defining a longitudinally extending lumenin the catheter wall. Preferably, the catheter is a delivery catheterhaving an about 9 French or less outer diameter, even more preferably anabout 8 French or less outer diameter. In an aspect of the invention thecatheter wall has a thickness of about 15 mil or less, and preferablyabout 10 mil or less, for at least a portion of its length, andpreferably over substantially its entire length. The at least onechannel can be formed using polymer shrink tube. In an aspect of theinvention the polymer shrink tube has an expanded inner diameter ofabout 0.150 inch over substantially the entire length of the tube. In afurther aspect of the invention the polymer shrink tube has a retractedinner diameter of about 0.100 inch over substantially the entire lengthof the tube. In a still further aspect of the invention, the at leastone channel can be formed using fluoropolymer shrink tube, as discussedabove. The fluoropolymer tube can comprise any suitable fluoropolymer asdiscussed above and may have an expanded inner diameter of about 0.150inch over substantially the entire length of the tube and may also havea retracted inner diameter of about 0.100 inch over substantially theentire length of the tube. Other polymer shrink tube may be used, suchas olefins, including chlorinated olefins, polyethylene terephthalate(PET), and polyvinyl chloride (PVC).

The outer polymer tube can comprise any suitable polymer. Preferredpolymers include thermoplastics such as PEBAX® polyether block amides,nylon, urethanes, polyethylene, polypropylene, FEP, etc. Particularlypreferred for the outer polymer tube is a material comprising PEBAX®polyether block amides, such as PEBAX® 6333.

It should be understood that although the inner surface of the outerpolymer tube is positioned over the outer surface of the fluoropolymertube, there is no requirement that the tube surfaces directly contacteach other. It may be desirable to provide an adhesive between thesematerials. Moreover, a reinforcing material such as a metal (e.g.,stainless steel or nitinol) or polymer support structure such asbraiding, coil, stylets, tubing, ribbon, or what-have-you can bepositioned between the tube surfaces to obtain desired properties. Itmay be desirable for the outer polymer tube to at least partially embedany reinforcing material (e.g. metal braid). Moreover, it may bedesirable for the outer polymer to flow through the reinforcement andbond to the fluoropolymer tube. In such a case, the fluoropolymer tubeouter surface can be chemically etched to aid in the adhesion betweenthe outer polymer tube and fluoropolymer tube.

The polymer film which can cover the at least one channel, can compriseany suitable polymer film material.

For example, the film material can be made from a thin tape of porousexpanded polytetrafluoroethylene (ePTFE) that can be helically wrappedabout the exterior of the catheter shaft. Preferred ePTFE films aregenerally made as taught by U.S. Pat. Nos. 3,953,566 and 4,187,390 toGore. Even more preferred ePTFE films can be made as taught by U.S. Pat.No. 5,476,589 to Bacino. Further examples of polymer films includepolyethylene (including ultra-high molecular weight polyethylene),polypropylene, polyamide, polyethylene terephthalate, fluorinatedethylene propylene (FEP), perfluoroalkoxy resin, polyurethane,polyester, polyimide, etc.

Most preferably, the wrapping is accomplished in two opposing directionsparallel to the length of the outer polymer tube, resulting in abias-ply construction. Although helically wrapping a tape of polymerfilm is a preferred embodiment, it is also possible to provide thepolymer film as a thin tubular structure that can coaxially enclose theentire outer polymer tube. Moreover, it is also possible to provide astrip of thin polymer tape material that covers the channel and isadhered to the surface of the outer polymer tube immediately adjacentboth sides of the channel. Suitable wrapping techniques are fullydescribed in, for example, commonly owned and co-pending U.S. PatentApplication Publication No. 2004/0193139, published Sep. 30, 2004. Asdescribed in the commonly owned application, the porous polymer tape canoptionally be provided with a thin, non-porous coating. Moreover, priorto wrapping the polymer tube, it may be desirable to fill the channel(at least partially or completely) with a material that will providestructural support to the at least one channel so that the dimensions ofthe channel will not be substantially altered by the film wrappingprocess. Of course, materials that can be easily removed from thechannel after film wrapping is completed are preferred and will beapparent to the skilled artisan.

The polymer tape is most preferably made from a thin porous expandedPTFE film that has been provided with a porous or non-porous coating of,or is at least partially imbibed with, a thermoplastic such as athermoplastic fluoropolymer, and preferably EFEP (ethylene tetra fluoroethylene based copolymer, available from Daikin America). An example ofa suitable wrapping technique includes using EFEP in combination withePTFE tape. The tape can have, for example, a width of about 6 mm and athickness of about 0.005 mm. The ePTFE film can be provided with anon-porous coating of EFEP on one or both sides. Moreover, the porosityof the ePTFE film can be at least partially or substantially completelyimbibed with EFEP. After the coated and/or imbibed film is cut intonarrow tape, the tape can be helically wrapped about the outer polymertube comprising PEBAX® polyether block amide. The wrapped catheter canthen be heated for about 5 minutes in a convection oven set at about160° C. to melt-bond the helically wrapped layers of the film together.Thereafter, the catheter can be removed from the oven and cooled to roomtemperature.

In an alternative embodiment, rather than using EFEP, a UV-curable orother light or radiation curable polymer could be used, thus allowingfor curing of the polymer without application of such high temperature.

In a preferred embodiment, the polymer comprises UV-curable polymer.UV-curable is defined as a material that will react under UV light toeither cure or form a durable bond. The UV light can be provided by alamp having a suitable voltage, a suitable strength, and a suitablewavelength. Curing with UV light may be carried out for any suitablelength of time, and the distance between the sample being cured and theUV lamp can be any suitable distance. All of the above parameters willbe readily determinable by one skilled in the art. In an aspect of theinvention the UV curable material can also be sensitive to visiblelight. However, preferred conditions are present only under the UVspectrum (100-400 nm). The preferred range is in the UVA spectrum(320-390 nm). Suitable UV-curable polymers include, for example,acrylated epoxies, acrylates, urethane acrylates, urethanemethacrylates, silanes, silicones, epoxides, epoxy methacrylates,triethylene glycol diacetate, and vinyl ethers. Specific examples ofthese polymers include acrylated aliphatic oligomers, acrylated aromaticoligomers, acrylated epoxy monomers, acrylated epoxy oligomers,aliphatic epoxy acrylates, aliphatic urethane acrylates, aliphaticurethane methacrylates, alkyl methacrylate, amine-modified oligoetheracrylates, amine-modified polyether acrylates, aromatic acid acrylate,aromatic epoxy acrylates, aromatic urethane methacrylates, butyleneglycol acrylate, stearyl acrylate, cycloaliphatic epoxides, cylcohexylmethacrylate, ethylene glycol dimethacrylate, epoxy methacrylates, epoxysoy bean acrylates, glycidyl methacrylate, hexanediol dimethacrylate,isodecyl acrylate, isooctyl acrylate, oligoether acrylates,polybutadiene diacrylate, polyester acrylate monomers, polyesteracrylate oligomers, polyethylene glycol dimethacrylate, stearylmethacrylate, triethylene glycol diacetate, and vinyl ethers. PreferredUV-curable polymers include, for example, medical grade UV-curablepolymers such as DYMAX® 204 CTH UV-curable polymer and DYMAX® 206 CTHUV-curable polymer (both commercially available medical grade UV-curablepolymers available from DYMAX Corporation, Torrington, Conn.).

In addition to EFEP and UV-curable polymers, further suitable polymermaterials can include, for example, thermoplastics, thermosets, pressuresensitive adhesives, heat-activated adhesives, and chemically activatedadhesives.

Preferred polymer materials include thermoplastics that melt below thetemperature that would cause the outer tube and/or polymer film to melt.This allows the polymer tape wraps (when used) to fuse together withoutmelting the polymer tape, without reflowing the outer polymer tube and,thus, without losing the pattern embossed into the outer polymer tube.UV-curable adhesives can be particularly attractive in this aspect ofthe invention. Particularly attractive are medical grade UV-curablepolymers, such as the above-mentioned DYMAX® 204 CTH and DYMAX® 206 CTH.

The particular polymer used will, of course, depend upon the particularembodiment and desired results. Such polymers can be provided in liquidor solid form. In an aspect of the invention, polymers include, forexample, THV (tetrafluoroethylene, hexafluoropropylene, and vinylidefluoride, available from Dyneon), EFEP (Daikin America), PE(polyolefin), polyamides, polyacryl-amides, polyesters, polyolefins(e.g., polyethylene), polyurethanes, and the like.

Suitable polymer application means include any method known in the art.With regard to porous polymer films, suitable application means include,for example, coating techniques (e.g., dip coating), solvent imbibing,vacuum assisted coating, pressure assisted coating, nip coating, andother suitable means which result in the polymer filling at least someof the porosity of the porous polymer film.

It may be desirable to utilize a solvent to aid in providing polymer tothe porosity of the polymer film. The ratio of solvent material topolymer can vary and will be readily determinable by the skilledartisan. A 50/50 by weight solvent to polymer solution may beparticularly acceptable. Preferable solvent materials will be readilyapparent to one skilled in the art and include, for example, alcohols,ketones, etc. Methyl ethyl ketone (MEK) may be one particularlyattractive solvent. When a solvent material is utilized, the solventmaterial can be easily removed or driven off once the polymer isprovided to at least some of the porosity of the porous film as desired.

The invention also relates to a method for forming catheters having atleast one lumen located in the catheter wall and extending for at leasta portion of the length of the catheter. The at least one lumen can beformed by utilizing the polymer shrink tubing, and particularlyfluoropolymer shrink tubing, according to the present invention. Theinvention further relates to a method of forming catheters having easilytailorable properties and/or altered cross-sections.

For example, a cylindrical, flowable plastic material (such as Pebax(polyether block amides), having a generally central, longitudinallyextending lumen, is provided. In an aspect of the invention, acylindrical mandrel having a diameter equal to about the desired innerdiameter of a tubular member such as a catheter can first be provided.The outer surface of the mandrel can be coated with a lubriciousmaterial, such a PTFE. The cylindrical, flowable plastic materialoptionally could first be located over the mandrel to provide structuralsupport to the flowable plastic material during further processing.Furthermore, a suitable, cylindrical polymer shrink tube having an innerand an outer surface, with the inner surface having at least onethree-dimensional pattern thereon, can be placed over the flowableplastic tube. Thereafter, a suitable energy source, such as hot air canbe applied to the shrink tube to shrink the tube around the outersurface of the flowable plastic tube, causing the at least onethree-dimensional pattern to be embossed into the flowable plastic tube.The temperature (and duration of application of heat) should besufficient to shrink the tubing and cause the pattern to be embossedinto the flowable plastic tube, but not so high (and/or so long induration) as to cause the three-dimensional pattern to lose its form.

This embodiment is demonstrated in FIG. 3, where three-dimensionalpattern 1 is a longitudinally extending rib on the inner surface ofshrink tube 10. As can be seen, longitudinally extending rib 1 extendsinto flowable plastic tube 20 during and after the heating stepdescribed above. When shrink tube 10 is removed, a catheter body havinga tailored cross-section is obtained, in this case a non-circularcross-section due to the longitudinally extending channel formed in theplastic tube. This will, of course, alter certain properties of thecatheter body, such as bending characteristics, when compared tocatheters without the longitudinally extending channel. It should beunderstood that other three-dimensional patterns could be embossed intothe flowable plastic tube to result in various tailored cross-sectionsand result in various altered catheter properties.

FIG. 4 shows an alternative embodiment, which further comprises athin-walled (e.g., about 1.5 mil wall thickness) tubular liner 30 of asuitable material (such as PTFE) as the inner member of the tubularstructure. Obviously, this embodiment can be obtained by first placingthe thin-walled liner over the mandrel (if used) and then following thesequence described above. FIG. 5 shows, in cross section, a furtheralternative embodiment which further includes metal coil (such asstainless steel or nitinol coil) material 40 located between the inner,thin-walled liner 30 and the flowable plastic tube 20. Of course, themetal coil could be at least partially embedded into the flowableplastic tube, as discussed above. In an aspect of the invention themetal coil is a helically wrapped stainless steel coil measuring about0.002″×0.012″ that can extend any desired length of the tube. Asmentioned above, the metal coil material 40 could be substituted withany desirable reinforcing material, which will be readily apparent tothose skilled in the art.

In an aspect of the invention polymer shrink tube is used to cause theat least one three-dimensional pattern to be embossed into the flowableplastic tube and to cause or assist the flowable plastic to embed theoptional reinforcing material. This is preferably accomplished during asingle heating (or other energy application) step. For example, anextruded PTFE tube could be placed over a mandrel, as discussed above. Asuitable reinforcing material, such as stainless steel or nitinol coilcould be placed over the PTFE tube. A flowable plastic tube could beplaced over the reinforcing material and then a polymer shrink tubehaving at least one three-dimensional pattern on the inner surfacethereof could be placed over the flowable plastic tube. Suitable energy,such as heat, could then be applied to the assembly to cause the polymershrink tube to shrink. As the tube shrinks, the flowable plastic tubecan at least partially embed, or substantially completely embed, themetal reinforcement while, at the same time, the at least onethree-dimensional pattern is embossed into the flowable plastic tube.The at least one three-dimensional pattern could be a longitudinallyextending rib, which results in a longitudinally extending channel beingembossed into the flowable plastic tube. After allowing the assembly tocool, the polymer shrink tube can be removed and the at least onepattern could be covered with polymer film, as discussed above.

As shown in FIG. 5, shrink tube 10 has been removed, thus resulting inlongitudinally extending channel 3. Moreover, the outer polymer tube 20has been provided with polymer film cover 50, thus defining alongitudinally extending lumen in the outer polymer tube 20. In anaspect of the invention, polymer film 50 is provided as a helical wrapof ePTFE at least partially imbibed with suitable polymer, such as UVcurable polymer or EFEP, as described above.

It should be understood that any number of longitudinally extendingchannels could be provided to the embodiment discussed above, byproviding a plurality of longitudinally extending ribs to the shrinktubing 10. In an aspect of the invention, four longitudinally extendingchannels, each about 90° apart, are provided. In a further aspect of theinvention, each of the four channels has dimensions essentially equal toone another. In a further aspect of the invention, each channel has awidth of about 0.015 inch and a depth of about 0.007 inch. Once coveredwith suitable polymer film, four longitudinally extending lumens wouldbe obtained. These lumens could be used, for example, to deliverinflation fluid to an expandable member on a distal end of a catheter,to pass strings/wires/or fluids down the length of a catheter, todeliver electrical, sensing, mechanical steering, or device deploymentdevices, etc. Moreover, the lumen(s) could be used to locate at leastone material in the catheter wall that will alter at least one propertyof the catheter. For example, a stiffening wire could be located in alumen for part of the length of the catheter, or for the entire lengthof the catheter. The stiffening wire could be located in the lumenbefore or after providing the polymer film cover. Further, the lumencould be filled, partially or completely, with any suitable material(e.g., polymer, metal, etc.) to alter the catheter's stiffness along atleast a portion of the length of the catheter. According to this aspectof the invention it is possible to produce catheters having varyingproperties (e.g., stiffness) along the length of the catheter.

Turning to FIG. 6, there is shown in longitudinal cross section, onepotential catheter embodiment according to the present invention. Asshown, the catheter 100 includes an inflatable member 5 located at thedistal end 7 of the catheter. Thin-walled liner 30 (e.g., fluoropolymersuch as PTFE) extends for the length of the catheter and defines inner,centrally located lumen 6. Positioned over the inner liner 30 is polymertube 20, which also can extend for the length of the catheter. Not shownis optional reinforcing material, such as metal coil or braid (describedabove), which can also extend for the length of the catheter and bepositioned over thin-walled liner 30 and optionally embedded intopolymer tube 20. Polymer film wrap 50 can also extend for the length ofthe catheter and cover longitudinally extending channel 3, thus defininglongitudinally extending lumen in polymer tube 20. As shown,longitudinally extending channel 3 can function as an inflation lumenand is in fluid communication with inflation port 4 and the interior ofinflatable member 5.

As should be understood, catheter 100 can be appropriately sized for anynumber of desirable applications, such as those discussed in thecommonly owned patents and patent applications, discussed above.Moreover, there is no requirement that an inflatable member is locatedat the distal end of the catheter, or provided at all. Furthermore,additional lumens could be provided in polymer tube 20. Such lumenscould be used to allow for delivery of delivery catheters,balloon-on-a-wire devices, thrombectomy removal devices, steering wires,diagnostic catheters, angiographic catheters, etc., as well as to beused to locate at least one material in the catheter wall such as astiffening wire, as discussed above.

While particular embodiments of the present invention have beenillustrated and described herein, the present invention should not belimited to such illustrations and descriptions. It should be apparentthat changes and modifications may be incorporated and embodied as partof the present invention within the scope of the following claims.

1. A catheter comprising: a fluoropolymer tube having a proximal end, adistal end, an inner surface defining a longitudinally extending,generally central lumen and an outer surface; an outer polymer tubehaving a proximal end, a distal end, an inner surface and an outersurface, wherein the inner surface of the outer polymer tube ispositioned over the outer surface of the fluoropolymer tube; wherein atleast one channel is located in the outer polymer tube, the at least onechannel measuring about 7 by about 15 mils and extending for at least aportion of the length of the catheter; and polymer film covering atleast a portion of the length of the at least one channel, thus definingat least one longitudinally extending lumen in the catheter.
 2. Thecatheter of claim 1, further comprising a reinforcing material incontact with the outer polymer tube.
 3. The catheter of claim 2, whereinthe reinforcing material comprises metal.
 4. The catheter of claim 3,wherein the metal comprises a material selected from the groupconsisting of stainless steel and nitinol.
 5. The catheter of claim 3,wherein the metal is a coil construction.
 6. The catheter of claim 2,wherein the reinforcing material is embedded by the outer polymer tube.7. The catheter of claim 1, wherein the catheter has an outer diameterof about 9 French or less.
 8. The catheter of claim 7, wherein thecatheter has an outer diameter of about 8 French or less.
 9. Thecatheter of claim 1, wherein the fluoropolymer tube comprises a materialselected from the group consisting of polytetrafluoroethylene andfluorinated ethylene propylene.
 10. The catheter of claim 9, wherein thefluoropolymer tube comprises polytetrafluoroethylene.
 11. The catheterof claim 1, wherein the at least one channel extends from the proximalend to the distal end of the outer polymer tube.
 12. The catheter ofclaim 11, wherein an inflatable member is located at the distal end ofthe catheter and the at least one channel is in fluid communication withthe interior of the inflatable member.
 13. The catheter of claim 12,wherein the outer polymer tube comprises at least a second channel. 14.The catheter of claim 6, wherein the fluoropolymer tube comprisespolytetrafluoroethylene, the outer polymer tube comprises polyetherblock amide, the polymer film comprises expandedpolytetrafluoroethylene, and the reinforcing material comprisesstainless steel coil.
 15. A method of creating an external embossedpattern on the exterior of a cylindrical device comprising: providing apolymer tube having at least an exterior surface; providing a shrinktube having an inner and an outer surface, the inner surface having athree-dimensional pattern thereon; placing the shrink tube around thepolymer tube; applying sufficient energy to the shrink tube so as toshrink the shrink tube around the exterior of the polymer tube, causingat least a portion of the three-dimensional pattern to become embossedinto the exterior surface of the polymer tube.
 16. The methods of claim15, wherein the polymer tube is placed over a mandrel prior to applyingenergy to the shrink tube.
 17. The method of claim 15, furthercomprising removing the shrink tube from the polymer tube, leaving acylindrical device with an embossed pattern therein.
 18. The method ofclaim 17, further comprising providing sufficient energy to cause thepolymer tube to flow.
 19. The method of claim 17, wherein the embossedpattern increases the outer surface area of the cylindrical device. 20.The method of claim 17, wherein the three-dimensional pattern comprisesat least one rib extending along the inner surface of the shrink tube,whereby a channel is formed along the cylindrical device complementaryto the rib.
 21. The method of claim 17, wherein the cylindrical deviceis a catheter having a length and wherein the three-dimensional patternprovides a channel that extends for at least a portion of a length ofthe catheter.
 22. The method of claim 21, further comprising providing apolymer film to cover at least a portion of the channel.
 23. The methodof claim 22, wherein the polymer film is in the form of tape wrappedabout at least a portion of the catheter.
 24. A method for forming acatheter having a proximal end and a distal end comprising the steps of:providing a fluoropolymer tube having a proximal end, a distal end, aninner surface defining a longitudinally extending, generally centrallumen, and an outer surface; providing an outer polymer tube having aproximal end, a distal end, an inner surface, and an outer surface,wherein the inner surface of the outer polymer tube is positioned overthe outer surface of the fluoropolymer tube; providing a polymer shrinktube having a proximal end, a distal end, an inner surface, and an outersurface, the inner surface having at least one three-dimensional patternthereon; placing the polymer shrink tube around the outer polymer tube,with the polymer shrink tube inner surface adjacent the outer surface ofthe outer polymer tube; applying sufficient energy to the shrink tube soas to shrink the shrink tube around the outer polymer tube, causing atleast a portion of the at least one three-dimensional pattern to becomeembossed into the outer polymer tube; removing the polymer shrink tube;and covering at least a portion of the at least one three-dimensionalpattern with polymer film.
 25. The method of claim 24, wherein the atleast one three-dimensional pattern includes at least one rib thatembosses at least one channel into the outer polymer tube.
 26. Themethod of claim 25, wherein the at least one channel is a longitudinallyextending channel.
 27. The method of claim 26, further comprising areinforcing material in contact with the outer polymer tube.
 28. Themethod of claim 27, wherein the reinforcing material comprises metal.29. The method of claim 28, wherein the metal is selected from the groupconsisting of stainless steel and nitinol.
 30. The method of claim 27,wherein the metal is a coil construction.
 31. The method of claim 27,wherein the reinforcing material is embedded by the outer polymer tubeduring the step of applying sufficient energy.
 32. The method of claim26, wherein the at least one longitudinally extending channel measuresabout 0.007 inch by about 0.015 inch.
 33. The method of claim 26,wherein an expandable member is located at the distal end of thecatheter and the at least one longitudinally extending channel is influid communication with the interior of the expandable member.
 34. Themethod of claim 33, wherein the expandable member is an occlusionballoon.
 35. The method of claim 24, wherein the polymer film comprisesa material selected from the group consisting ofpolytetrafluoroethylene, polyethylene, polypropylene, polyamide,polyethylene terephthalate, fluorinated ethylene propylene,perfluoroalkoxy resin, polyurethane, polyester, and polyimide.
 36. Themethod of claim 35, wherein the polytetrafluoroethylene is porous,expanded polytetrafluoroethylene.
 37. The method of claim 36, furthercomprising providing at least a second polymer to the expandedpolytetrafluoroethylene.
 38. The method of claim 37, wherein the secondpolymer is provided by at least one of the following methods, coating,imbibing, vacuum assisted coating, nip coating, and dip coating.
 39. Themethod of claim 37, wherein the second polymer is imbibed into at leastsome of the porosity of the expanded polytetrafluoroethylene.
 40. Themethod of claim 37, wherein the second polymer is provided as at least apartial surface coating to one or more sides of the expandedpolytetrafluoroethylene film.
 41. The method of claim 39, whereinsubstantially all of the porosity of the expandedpolytetrafluoroethylene is imbibed with the second polymer.
 42. Themethod of claim 37, wherein the second polymer is selected from thegroup consisting of thermoplastics, thermosets, pressure sensitiveadhesives, heat-activated adhesives, chemically-activated adhesives, andUV-curable polymers.
 43. The method of claim 42, wherein the secondpolymer is selected from the group consisting of ethylene tetra fluoroethylene based copolymers and UV-curable polymers.
 44. The method ofclaim 43, wherein the second polymer is UV-curable.
 45. The method ofclaim 43, wherein the outer polymer tube is selected from the groupconsisting of polyether block amides, nylon, urethanes, polyethylene,polypropylene, and fluorinated ethylene propylene.
 46. The method ofclaim 43, wherein the outer polymer tube comprises at least polyetherblock amide.
 47. The method of claim 26, wherein four longitudinallyextending channels are formed in the outer polymer tube.
 48. The methodof claim 47, wherein the four longitudinally channels are each about 90degrees apart.
 49. The method of claim 48, wherein each of the fourlongitudinally extending channels has a width of about 0.015 inch and adepth of about 0.007 inch.